I recently started to use Copy.com. It seems that it's the best cloud
company so far. With unlimited 5GB referrals. And for the security thing,
copy.com provides AES-256-SHA server-side encryption.

For the security paranoids, I would recommend SpiderOak. Offers the same
encryption, but SpiderOak takes the extra step of encrypting the decryption
key itself. This key can itself only be decrypted with the user's password,
which SpiderOak never knows (the full authentication process is laid out
here: https://spideroak.com/engineering_matters#user_auth).

Securing Apache Web Server with thawte Digital Certificate In this guide we
examine the importance of Apache-SSL and who needs an SSL certificate. We
look at how SSL works, how it benefits your company and how your customers
can tell if a site is secure. You will find out how to test, purchase,
install and use a thawte Digital Certificate on your Apache web server.
Throughout, best practices for set-up are highlighted to help you ensure
efficient ongoing management of your encryption keys and digital
certificates.

Securing Apache Web Server with thawte Digital Certificate
In this guide we examine the importance of Apache-SSL and who needs an SSL certificate. We look at how SSL works, how it benefits your company and how your customers can tell if a site is secure. You will find out how to test, purchase, install and use a thawte Digital Certificate on your Apache web server. Throughout, best practices for set-up are highlighted to help you ensure efficient ongoing management of your encryption keys and digital certificates.